VRDP not available when quickly power cycling VM -> Fixed in SVN/3.1.4

Description

When shutting down a VBox with VRDP enabled, and immediatly starting the VBox again, the TCP port for VRDP can't be opened if there was a RDP session connected to the VBox.

To verify, start a VM with VRDP enabled (VBoxHeadless -s test). Next, connect an RDP client to that VM. Now, shutdown the host. When the shut down is done, the RDP Client will be disconnected by the server, leaving the TCP socket in the TIME_WAIT state.